In my film class, our professor mentioned some type of fiberglass gels that you use to change the color of the light. However, I don't think I heard him correctly and now someone wants to put it over their outdoor lights to make them red for the holidays. I'm pretty sure I have the correct material (the woven fiberglass) in mind, but I just want to make certain. if this is the incorrect material, what else can I use to put over my lights as a gel to make the light reds.